RISC-V: Add test for vec_duplicate + vwmulu.vv signed combine with GR2VR cost 0,...

RISC-V: Add test for vec_duplicate + vwmulu.vv signed combine with GR2VR cost 0, 1 and 15

Add asm dump check and run test for vec_duplicate + vwmulu.vv
combine to vwmulu.vx, with the GR2VR cost is 0, 2 and 15.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u16.c: Add asm check
	for vwmulu.vx.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_widen.h: Add test helper
	macros.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_widen_data.h: Add test
	data for vwmulu.vx run test.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vwmulu-run-1-u64.c: New test.

Signed-off-by: Pan Li <pan2.li@intel.com>